Structural, optical and luminescence features of Er3+/Yb3+ co-doped sol-gel silica glasses

The transparent erbium and ytterbium co-doped silica glasses having pink tint were obtained using a new variant of the sol-gel synthesis method. The amount of Er3+/Yb3+ cations introduced into the glass was quantitatively monitored by energy dispersive X-ray analysis. The produced Er3+/Yb3+ co-doped silica glasses (0.25-5 wt. Er2O3 and 2 wt. % Yb2O3) have a high optical homogeneity and contains OH groups in amount of 0.4-1 wt. %. Optical properties of samples were analyzed using UV-VIS absorption and luminescence spectroscopy. The changes in the luminescence spectra of glasses are related to the transitions of Er3+ and Yb3+ ions from glass matrix and correlate well with optical adsorption data. Upon excitation by a 978 nm Xe lamp, up-conversion emissions from Er3+ ions centered at 540 and 650 nm were greatly enhanced as the concentration of erbium oxide in the glasses increased. The proposed sol-gel synthesis method allows fabrication of the complex glass systems which have potential in the application of optoelectronic areas.